Expect to pay at about $140,000 and even then, the Cleveland Cavaliers forward is not likely to say yes.

Opendorse, a company that specializes in executing and monetizing digital and social media campaigns for athletes, says a tweet from James, who has 23.2 million followers, has the highest value of any U.S. athlete. Each tweet from James has a media value of $139,474, the company said.

LeBron James and his two thumbs are worth $140,000 when it comes to tweeting out sponsored content. Kim Klement/USA TODAY Sports

"We're basically saying that the value of one LeBron tweet is worth $140,000," said Opendorse CEO Blake Lawrence. "And with that, you will reach 23 million people. It would cost you five times more to reach that many people with a TV ad."

Lawrence's company figures out how much a particular tweet, Facebook or Instagram post is worth by determining a celebrity's true reach, activity, and quality and overall level of engagement of their audience of followers.

Rounding out the top five athletes whose single tweet would provide a company's product or service the most value are Kevin Durant ($66,553), Kobe Bryant ($42,389), Floyd Mayweather ($34,924) and Dwight Howard ($34,290).

Despite the big numbers, Lawrence said most companies pay athletes between $1,000 and $2,500 for a single tweet. The most his company has sold a one-off tweet for was for $20,000 during last year's NFL playoffs when a New England Patriots player, who he said he can't disclose, took the bounty.

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Four of the top five athletes in terms of value per tweet endorsement are NBA players, with LeBron James far and away the most expensive.

Cost

LeBron James

$139,474

Kevin Durant

$66,553

Kobe Bryant

$42,389

Floyd Mayweather

$34,924

Dwight Howard

$34,290

-- Opendorse

Lawrence said he brought a one-tweet, six-figure deal to LeBron's team, which recently passed.

"The big guys are looking for a fully integrated endorsement deal that includes social media," Lawrence said. "But there are only so many athletes that can get that type of home run."

Opendorse values the tweets themselves for a marketer's negotiation and then manages the social part of contract, including putting in the tweets themselves into an athlete's timeline.

"I think a lot of companies think they can't get a star athlete for less than $100,000," Lawrence said. "You can get [Baltimore Ravens quarterback] Joe Flacco to tweet about your company for less than $1,000 right now."